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Why do you think it has been so difficult to identify genes underlying schizophrenia?
Rachel asked to see a genetic counselor because she was concerned about developing schizophrenia. Her mother and maternal grandmother both had schizophrenia and were institutionalized for most of their adult lives. Rachel’s three maternal aunts are all in their 60s and have not shown any signs of this disease. Rachel’s father is alive and healthy, and his family history does not suggest any behavioral or genetic conditions. The genetic counselor discussed the multifactorial nature of schizophrenia and explained that many candidate genes have been identified that may be mutated in individuals with the condition. However, a genetic test is not available for presymptomatic testing. The counselor explained that based on Rachel’s family history and her relatedness to individuals who have schizophrenia, her risk of developing it is approximately 13%. If an altered gene is in the family and her mother carries the gene, Rachel has a 50% chance of inheriting it.
To describe: The difficulties to identify genes underlying schizophrenia.
Introduction: Schizophrenia is characterized by thought disorders, delusions, and anti-social behavior. This is much common in children and at least lasts for 6 months. Schizophrenia is found within a region of DNA located on chromosome 6. The genes underlying the disease are still unknown.
Explanation of Solution
Schizophrenia is a behavioral disorder that causes widespread human suffering. Several genetic studies have shown that hundreds of genes are linked to schizophrenia. Each gene contributes a small part to the risk of developing the disease.
Therefore, a mutation in a gene does not confirm the presence of schizophrenia. Similarly, if someone has schizophrenia with a mutation in a gene also does not mean that this mutation is responsible for the behavior of the respective person.
Hence, it is difficult to find genetic determinants underlying schizophrenia.
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Chapter 18 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
- If a test were available that could tell you whether you were likely to develop a disorder such as schizophrenia later in life, would you take the test? Why or why not? Rachel asked to see a genetic counselor because she was concerned about developing schizophrenia. Her mother and maternal grandmother both had schizophrenia and were institutionalized for most of their adult lives. Rachels three maternal aunts are all in their 60s and have not shown any signs of this disease. Rachels father is alive and healthy, and his family history does not suggest any behavioral or genetic conditions. The genetic counselor discussed the multifactorial nature of schizophrenia and explained that many candidate genes have been identified that may be mutated in individuals with the condition. However, a genetic test is not available for presymptomatic testing. The counselor explained that based on Rachels family history and her relatedness to individuals who have schizophrenia, her risk of developing it is approximately 13%. If an altered gene is in the family and her mother carries the gene, Rachel has a 50% chance of inheriting it.arrow_forwardA region on chromosome 6 has been linked to schizophrenia, but researchers have not found a specific gene associated with this disease. What steps would be necessary to locate the gene?arrow_forwardPerson A and person B are both worried they are going to develop a neurodegenerative disease. Unfortunately, person A has more reason to be worried than person B. Of the neurodegenerative disorders below, pick one and come up with one possible reason why person A is more likely to develop this disorder than person B, and also come up with one possible reason why person B is more likely to be protected from the disorder. For full credit, you must concoct TWO separate genetic, environmental, or lifestyle reasons that will make person A more likely, and person B less likely to develop the disease you’ve selected: Parkinson’s Alzheimer’s disease Huntington’s Multiple Sclerosisarrow_forward
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- Why Recessive CF disease alleles either produce no CFTR or produce nonfunctional or less functional versions of the protein?arrow_forwardn individual who has been diagnosed with schizophrenia may also have a mutation in the _____. a. DISC1 gene that controls differentiation and migration of neurons in brain development b. serotonin transporter gene that controls the reuptake of dopamine and serotonin in the brain c. DISC1 gene that controls the reuptake of dopamine and serotonin in the brain d. serotonin transporter gene that controls the types of glial cells that can help form serotonin in the brainarrow_forwardIn the introduction to this chapter, we discussed the role of famine during early prenatal development and how, through epigenetic effects, it influenced the health of individuals as adults. One effect that has been observed in people who were conceived during the Dutch Hunger Winter is that they suffer more cognitive decline later in life. If these individuals were autopsied after death, what differences might you expect to see in the chromatin of their brain cells? What do the mouse studies of cognition and epigenetic effects suggest?arrow_forward
- Lesch-Nyhan syndrome is due to a mutation in a gene that encodesa protein called hypoxanthine-guanine phosphoribosyltransferase(HPRT). HPRT is an enzyme that functions in purine metabolism.People afflicted with this syndrome have severe neurodegenerationand loss of motor control. The pedigree below contains severalindividuals with Lesch-Nyhan syndrome, shown with blacksymbols. Based on this pedigree, does this syndrome appearto be inherited by an autosomal recessive, autosomal dominant,X-linked recessive, or X-linked dominant pattern? Explainyour reasoning.arrow_forward“The one common denominator for all of the young children [with autism] is that early intervention does work, and it seems to improve the prognosis”. Who said this?arrow_forwardDescribe what nearsightedness, farsightedness, and astigmatism is. What is the complete epigenetic origin to include the genetic/biological origin and the environment influence related to these disordersarrow_forward
Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning